A lens barrel including a barrel and a cam barrel is disclosed. In the lens barrel, a groove part is formed in a fixed frame, a linear groove is formed in a rotatable barrel, and a driving pin is formed on the cam barrel. The driving pin engages with the linear groove through the groove part. In the lens barrel disclosed in Patent document 1, the groove part, the linear groove, and the driving pin are arranged at angular positions approximately trisecting a circumference around an optical axis, and a movable group is linearly moved according to the rotation of the rotatable barrel.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.